324 research outputs found
Dynamics and structure of liquids under special conditions: water confined in giant polyoxometalates and co2-brine mixtures
L'estructura i la dinà mica dels lÃquids varien sota determinades condicions, tals com sota confinament o en presència d'ions. Aquesta tesi es divideix en dues parts. En la primera part, s'han estudiat l'estructura i la dinà mica d'aigua confinada en polyoxomolibdats gegants, per mitjà de simulacions de dinà mica molecular (DM) a condicions normals de temperatura i pressió. Els resultats obtinguts mostren que l'aigua tendeix a organitzar-se en capes concèntriques de la famÃlia de les buckyball. Les posicions d'aquestes capes coincideixen amb resultats experimentals de raigs X per aquest sistema a baixa temperatura. S'han calculat un gran nombre de propietats estructurals i dinà miques, algunes de les quals s'han comparat amb dades experimentals i de simulació per micel•les reverses de grandà ria similar amb un resultat satisfactori.
La segona part de la tesi es centra en el cà lcul de la difussivitat del diòxid de carboni (CO2) en salmorra sota les condiciones termodinà miques representatives d’aqüÃfers salins subterranis mitjançant simulacions de dinà mica molecular. S'han calculat els coeficients de difusió mà ssics i d'autodifusió del CO2, la conductivitat elèctrica de la barreja, aixà com els temps de relaxació rotacional del CO2 per totes les condicions. Aquests resultats constitueixen la primera estimació de coeficients de difusió mà ssics i temps de relaxació rotacional del CO2 en aqüÃfers salins subterranis.The structure and dynamics of liquids are distorted under special conditions, such as under confinement, or in the presence of ions. This thesis is divided into two parts. In the first part, we have studied the structure and dynamics of water confined in giant polyoxomolybdate molecular clusters by means of molecular dynamics (MD) simulations at ambient conditions. We observe that water organizes in concentric layered structures of the buckyball family, which agree with X-ray data for these systems at low temperature. Several structural and dynamical data are provided and compared to experimental and theoretical analyses for reverse micelles of similar size, where qualitative agreement is observed.
The second part of the thesis is devoted to the calculation of the diffusivity of carbon dioxide (CO2) in brine under the thermodynamic conditions representative of deep saline aquifers through MD simulations. We have calculated CO2 mass and self diffusion coefficients, electrical conductivities, as well as rotational relaxation times. These results are the first estimation of mass diffusion and rotational relaxation times of CO2 in deep saline aquifers
Cut elimination for Zermelo set theory
We show how to express intuitionistic Zermelo set theory in deduction modulo
(i.e. by replacing its axioms by rewrite rules) in such a way that the
corresponding notion of proof enjoys the normalization property. To do so, we
first rephrase set theory as a theory of pointed graphs (following a paradigm
due to P. Aczel) by interpreting set-theoretic equality as bisimilarity, and
show that in this setting, Zermelo's axioms can be decomposed into
graph-theoretic primitives that can be turned into rewrite rules. We then show
that the theory we obtain in deduction modulo is a conservative extension of (a
minor extension of) Zermelo set theory. Finally, we prove the normalization of
the intuitionistic fragment of the theory
Completions of Implicative Assemblies
We continue our work on implicative assemblies by investigating under which
circumstances a subset of the separator gives rise to
a full lex subcategory of the quasitopos
of all implicative assemblies such that
. We establish a
characterisation. What is more, this characterisation is relevant to the study
of 's ex-completion, which turns out to be a topos
Relative normalization
G{\"o}del's second incompleteness theorem forbids to prove, in a given theory
U, the consistency of many theories-in particular, of the theory U itself-as
well as it forbids to prove the normalization property for these theories,
since this property implies their consistency. When we cannot prove in a theory
U the consistency of a theory T , we can try to prove a relative consistency
theorem, that is, a theorem of the form: If U is consistent then T is
consistent. Following the same spirit, we show in this paper how to prove
relative normalization theorems, that is, theorems of the form: If U is
1-consistent, then T has the normalization property
A lambda-calculus with constructors
(avec annexes)International audienceWe present an extension of the lambda(eta)-calculus with a case construct that propagates through functions like a head linear substitution, and show that this construction permits to recover the expressiveness of ML-style pattern matching. We then prove that this system enjoys the Church-Rosser property using a semi-automatic `divide and conquer' technique by which we determine all the pairs of commuting subsystems of the formalism (considering all the possible combinations of the nine primitive reduction rules). Finally, we prove a separation theorem similar to Böhm's theorem for the whole formalism
El carst de sa Malafetge
[cat] Els autors, després d’una llarga prospecció espeleològica, presenten 15 formacions endocà rstiques situades a la serra de Son Camps (serra de na Burguesa), amb els seus respectius aixecaments topogrà fics. Destaquen, pel seu recorregut, l’avenc des Cérvol (210 m), i, per l’abundant i variat concrecionament, la cova de sa Fantasia.[eng] After a long speleological exploration, the authors present 15 karstic caves situated on the Serra de Son Camps (Serra de Na Burguesa), with their respective surveys. Noteworthy are the Avenc des Cérvol, with a 210 meter survey length, and the Cova de sa Fantasia, for the abundance and variety of its speleothems.[ita] Gli autori, dopo una lunga prospezione speleologica, presentano 15 forme endocarsiche, con i suoi rispettivi innalzamenti topografici, che si situano nella Serra de Son Camps (Serra de na Burguesa). Risaltano, per il suo percorso, l’Avenc des Cervol (210 m), e per l’abbondanza e varietà del concrezionamento, la Cova de sa Fantasi
Les coves de cala Anguila
[cat] Presentam la topografia i la descripció de set cavitats del litoral de Manacor, que es troben a la urbanització de Portocristo Novo. Aquestes formacions endocà rstiques es localitzen a la plataforma tabular postorogènica del Llevant i almenys sis d'elles són de la tipologia anomenada coves de la zona de mescla costanera. La cavitat més destacada del treball és la cova Genovesa o cova d'en Bessó amb un recorregut projectat de 2447 m dels quals 1845 m són subaquà tics.[eng] We present the surveys and descriptions of seven costal-lying caves within the Portocristo Novo urbanisation, Manacor municipal district. These caves are located in a tabular platform postorogenetic to the Serres Llevant and at least six of them having a typology associated with the costal mixing-zone. The most noteworthy cave is the Cova Genovesa, or Cova d'en Bessó, with a survey length of 2447 m (1845 m subaquatic).[spa] Presentamos la topografÃa y la descripción de siete cavidades del litoral de Manacor, situadas en la urbanización de Portocristo Novo. Las formaciones endokársticas se localizan en la plataforma tabular postorogénica del Llevant y al menos seis de ellas pertenecen a la tipologÃa denominada cuevas de la zona de mezcla costera. La cavidad más destacada del trabajo es la Cova Genovesa o Cova d'en Bessó con un recorrido proyectado de 2447 m de los cuales 1845 m. son subacuáticos
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